It has been used as a standard unit of weight measurement since the time of the French revolution, based on the precise mass of a lump of metal held in Paris. But the kilogram may be about to be given ...

Out with the old — kilogram, that is. Scientists will soon ditch a specialized hunk of metal that defines the mass of a kilogram. Oddly enough, every measurement of mass made anywhere on Earth is tied ...

A kilo is a kilo is a kilo, right? Wrong. Monday marks World Metrology Day, and this year’s edition sees a big change in the way the kilogram unit is defined. In November last year, scientists and ...

The new kilogram (unit of weight) and three other new base units - ampere (electric current), Kelvin (temperature) and mole (amount of substance such as atoms) - will now not be based on 'physical ...